Oiling system



g- ,1 R. L. TRAPP ETAL 3,144,095

OILING SYSTEM Filed April 27, 1962 INVENTORS. iamser 1. 72 4 65:41 4 4"BY United States Patent 3,144,095 OILING SYSTEM Robert L. Trapp andGerald Haft, Milwaukee, Wis., as-

signors to Outboard Marine Corporation, Waukegan, 11]., a corporation ofDelaware Filed Apr. 27, 1962, Ser. No. 190,661 6 Claims. (Cl. 184-6) Theinvention relates to internal combustion engines and especially toarrangements for oiling such engines. Still more particularly, theinvention relates to arrangements for oiling machines, such as internalcombustion engines, having two or more pistons and associated separatecrankcases.

The invention has for its principal object the provision of an improvedarrangement for lubricating the crankshaft, connecting rod bearings,Wrist pin bearings, and piston of an internal combustion engine. In itspreferred form, the invention provides an oiling arrangement for amulti-cylinder engine wherein lubricating oil is supplied directly froman oil source through an oil pump to separate, substantially closedcrankcases which are respectively associated with at least one pair ofoppositely acting pistons and which are subject to cyclical pressurevariation in response to piston movement. In addition, the inventionprovides for controlling the flow of oil to the several separatecrankcases of a multicylinder engine by the pressures created in thecrankcases as an incident to piston movement in the cylinders.

The invention also provides for an arrangement for shutting down theengine in the event that the oil supply for the pump reaches apredetermined minimum level, Other objects and advantages of theinvention will be apparent by reference to the following description andthe accompanying drawings of one embodiment.

In the drawings:

FIGURE 1 is a partially sectioned and broken away,

diagrammatic view illustrating a lubrication arrangement embodyingvarious features of the invention;

FIGURE 2 is a fragmentary, enlarged sectional view of a portion of thecylinder block shown in FIGURE 1;

FIGURE 3 is a fragmentary, enlarged sectional view of the pumpincorporated in the arrangement shown in FIGURE 1;

FGURE 4 is a sectional View taken generally along line 44 of FIGURE 3;and

FIGURE 5 is a sectional view taken generally along line 55 of FIGURE 3and showing a slightly modified form of piston.

The oiling arrangement illustrated in FIGURE 1 is shown in associationwith a conventional twostroke.

engine 9 having separate crankcases 10 and 12 for a pair of parallelcylinders 11 and 13 formed in a cylinder block 15 including a commonwall 17 separating the crankcases 10 and 12. Extending through bothcrankcases 10 and 12 adjacent one end of the block 15 is a crankshaft19. Oppositely operable in the usual manner in each of the cylinders 11and 13 are pistone 21 and 22 which are respectively connected to thecrankshaft 19 by connecting rods 23 and 24. Each cylinder is providedwith a spark plug 25 which is electrically connected to an ignitionsystem 26 (partially shown in diagrammatic form). Also associated witheach of the pistons 21 and 22 are usual intake, transfer and exhaustports (not shown). All of the foregoing elements are of Well knownconstruction and need not be further described.

Lubricating oil is supplied to the crankshaft 19, to the wrist pin andconnecting rod bearings, and to the pistons by an arrangement comprisingan oil pump 27 which is desirably driven by the crankshaft 19 and byconduit means 29, including a first portion connected to the oil pump 27and two branch portions which are 3,144,095 Patented Aug. 11., 1964connected to the first portion and to the respective crankcases. The oilpump 27 is constructed so as to deliver generally uniform quantities ofoil through the conduit means 29 in timed relation to the rotation ofthe crankshaft 19. In the disclosed construction, entry of oil into thecrankcases is controlled or governed by the movement of the pistons 21and 22.

More specifically, as is well known, the pistons 21 and 22, in atwo-stroke engine aligned in the manner shown in FIGURE 1, are connectedto the crankshaft 19 so that they travel, at all times, in directionsopposite to each other. Accordingly, at any particular time, one pistonis advancing toward top dead center and is thereby creating a negativepressure in its crankcase and in the connected branch portion in theconduit means 29. At the same time, the other piston is moving from topdead center, thereby creating a positive pressure in its crankcase andin the connected branch portion of the conduit means 29. As a result,the pressure differential between the respective crankcases 10 and 12,acting in the branch portions of the conduit means 29, directs the oilto that one of the crankcases which is at the lower pressure.

In the specifically disclosed construction, in which the crankcases 1t)and 12 are separated from each other by a common wall 17, the branchportions of the conduit means 29 are provided by the opposite ends of atransverse bore 31 (see especially FIGURE 2) which may be located at anyconvenient spot in the common wall 17. The first portion of the conduitmeans is provided by a second bore 33 which connects with the transversebore 31 at a distribution point intermediate its ends, and by a flexiblehose or conduit 35 connected to the oil pump 27 and to the second bore33 by a nipple 37.

Various oil pumps can be used to deliver oil to the conduit means 29.The disclosed oil pump 27 is especially suited to this function andcomprises, as best seen in FIGURES 3 through 5, a generally closedhousing 39 having, therein a cylindrical bore 41, and a cylindricalValve member 43 located in the bore 41. The housing 39 and the valvemember 43 are rotated relative to each other to provide the desiredpumping action. In the disclosed construction, the valve member 43includes a stub shaft 45 which extends through one wall 47 of thehousing and has mounted thereon a pulley or sheave 49 connected by abelt 51 to a co-operating pulley or sheave 53 on the crankshaft 19. Ofcourse, various arrangements can be used to drivingly connect thecrankshaft 19 to the oil pump 27. In addition, the ratio between therate of relative rotation between the housing 39 and the valve member 43can be adjusted as desired in order to regulate the quantity of oilbeing delivered to the crankcases 10 and 12.

Formed in the valve member 43 is a cavity 55 having therein a piston 57which is movable relative to one end 59 of the cavity 55 so as to definetherewith a pumping chamber 61 of variable volume. More specifically, inthe disclosed construction, the cavity 55 is. of cylindrical form and isdisposed in radial relation to the axis of the valve member 43.

The valve piston 57 is also a cylindrical member, having, at one end, astud 63 which extends into a guide bore extending from the end 59 of thecavity and has a rounded end for camming engagement with the wall of thebore 41. The other end of the valve piston can also be rounded off forcamming engagement with the wall of the housing bore 41. Morespecifically, the bore 41 also includes an annular recess 65 which is intangential eccentric relation to the remainder of the bore andcooperates with the rounded ends of the valve piston 57 to provide meansfor effecting movement of the valve piston toward and away from the end59 of the cavity in response to relative rotation between the valvemember 43 and the housing 39. The recess 65 is disposed in spacedrelation, axially of the housing bore 41, to an intake port 67 and adischarge port 69 so as to prevent communication therebetween.

More specifically, the intake and discharge ports 67 and 69 arerespectively connected to conduit means 68 leading to an oil source orstorage tank 73 and to the conduit 35. The discharge ports 67 and 69 arearranged in angularly spaced, diametrically opposed relation to eachother and are alternately connected to the pumping chamber 61 incidentto relative rotation between the housing 39 and the valve member 43 by aconduit or passageway 71 in the valve member 43. In order to provide atime interval for oil flow into and from the pumping chamber 61, each ofthe intake and discharge ports 67 and 69 is enlarged circumferentiallyaround the bore 41 within a radial angle of about 90.

As shown in FIGURE 5, the annular recess 65 is tangent to the bore 41 ata point spaced approximately midway between the intake and dischargeports 67 and 69 so that the valve piston 57 moves away from the cavityend 59 when the passageway 71 is connected to the intake port 67,thereby effecting filling of the pumping chamber 61 with oil. When thepassageway 71 is connected to the discharge port 69, the piston 57 isforced toward said one end 59 of said cavity to deliver oil from thepumping chamber 61. Thus, the disclosed pump functions both to suck oilinto the chamber 61 from the storage tank 73 and to subsequently forcethe oil out of the chamber.

FIGURE also shows a modified form of valve piston 57 in which the end ofthe stud 63 does not extend into engagement with the wall of the recess65 in the bore 41. In this arrangement, relative rotation between thevalve member 43 and the housing 39 serves to positively displace thevalve piston 57 toward the end 59 of the cavity 55, thereby dischargingoil from the cavity, and permits movement of the piston away from saidone end 59 of said cavity 55 when the valve member 57 is disposedrelative to the recess 65 as shown in FIGURE 5. In this instance, theoil in the intake port 67 is maintained under pressure so that the valvepiston 57 will be displaced outwardly of the cavity 55 by fluid pressurewhen the passageway 71 is connected to the intake port 67. Fluidpressure can be maintained in the intake port 67 by locating the oilstorage tank 73 in elevated relation to the oil pump 27.

The disclosed construction also provides means for automatic shortingout of the ignition system 26 in the event that the oil level in thestorage tank 73 reaches a predetermined low level. This means includes afloat 75 carried at one end of a pivotally mounted rod 77. I When theoil level reaches said predetermined low level, the float 75 positionsthe rod 77 so as to connect electrical leads which short out the primarycircuit of the ignition system 26. The float arrangement also providesmeans for warning of the approach of said predetermined low level in thetank by positioning the rod 77 to electrically connect a warning light81 to a battery 83 or other source of electrical energy.

While the disclosed dual cylinder engine has been described as aninternal combustion engine, the oiling arrangement is also adapted forother types of machines having two or more pistons and separatecrankcases. For instance, by omitting fuel supply, exhaust and sparkarrangements, and by including appropriate air intake and dischargeconnections, the cylinder 11 could be employed as an air pump driven bythe piston 22 acting in the cylinder 13.

Various of the features of the invention are set forth in the followingclaims.

What is claimed is:

1. In a device for lubricating the bearings of an internal combustionengine having cylinders, separate crank cases, a crankshaft in the crankcases provided with exposed cranks and pistons operatively connectedwith the cranks and reciprocable in the respective cylinders to developalternating pressure differentials on gas in said crank cases, theimprovement which consists of a duct communicating with each of saidcrank cases at a point in spaced relation to said crankshaft, an oilpressure line communicating with said duct and thereby with therespective crank cases, and means for supplying oil through said line tosaid duct for direct delivery alternately to the respective crank casesby reason of said pressure differentials.

2. An oiling device in accordance with claim 1 wherein said oilsupplying means comprises an oil pump including a housing having acylindrical bore therein with opposed intake and discharge ports, saiddischarge port being connected to said oil pressure line, a cylindricalvalve member carried in said bore for rotation relative to said housing,means connected to said crankshaft for effecting relative rotationbetween said valve memher and said housing, a cavity in said valvemember, a piston member movable in said cavity relative to one endthereof to define a pumping chamber of variable volume, conduit means insaid valve member for selectively establishing communication, incidentto relative rotation between said valve member and said housing, betweensaid one end of said cavity and said intake port and between said oneend of said cavity and said discharge port, and means operable, incidentto relative rotation between said valve member and said housing, foreffecting movement of said piston member in said cavity in co-ordinationwith the communication between said cavity and said intake and dischargeports.

3. An oiling device in accordance with claim 2 including a source of oilunder pressure connected to said intake port to effect movement of saidpiston member away from said one end of said cavity when said conduitmeans in said valve member is connected to said intake port, so as toeffect filling of said pumping cham- 4. An oiling device in accordancewith claim 1 wherein said oil supplying means comprises an oil pump, anoil' tank connected to said oil pump, and means for rendering saidengine inoperative when the oil in said tank reaches a predetermined lowlevel. 5. An oiling device for a two-stroke engine comprislng thecombination of a pair of parallel generally closed cylinders andcrankcases separated by a common wall, a piston operative in each ofsaid cylinders, a crankshaft connected by opposed cranks to said pistonsand operable in said crankcase, a port in said common wallinterconnecting said crankcases, said port being disposed in spacedrelation to said crankshaft, an oil pump drivingly connected to saidcrank shaft, and conduit means connecting said oil pump with said portwhereby oil is alternately delivered to said crankcases as an incidentto the pressure differential created by respective movement of saidpistons relative to said crankcases.

6. An oiling device in accordance with claim 5 including means drivinglyconnecting said oil pump with said crankshaft for operating said pump todeliver a predetermined quantity of oil for a given number ofrevolutions of said crankshaft.

References Cited in the file of this patent UNITED STATES PATENTS2,277,991 Leonard Mar. 31, 1942 2,651,999 Harrington Sept. 15, 19532,792,912 Kangas May 21, 1957 2,800,119 Schmidl July 23, 1957 2,903,091Goehring Sept. 8, 1959 FOREIGN PATENTS 10,667 Great Britain of 1913

1. IN A DEVICE FOR LUBRICATING THE BEARINGS OF AN INTERNAL COMBUSTION ENGINE HAVING CYLINDERS, SEPARATE CRANK CASES, A CRANKSHAFT IN THE CRANK CASES PROVIDED WITH EXPOSED CRANKS AND PISTONS OPERATIVELY CONNECTED WITH THE CRANKS AND RECIPROCABLE IN THE RESPECTIVE CYLINDERS TO DEVELOP ALTERNATING PRESSURE DIFFERENTIALS ON GAS IN SAID CRANK CASES, THE IMPROVEMENT WHICH CONSISTS OF A DUCT COMMUNICATING WITH EACH OF SAID CRANK CASES AT A POINT IN SPACED RELATION TO SAID CRANKSHAFT, AN OIL PRESSURE LINE COMMUNICATING WITH SAID DUCT AND THEREBY WITH THE RESPECTIVE CRANK CASES, AND MEANS FOR SUPPLYING OIL THROUGH SAID LINE TO SAID DUCT FOR DIRECT DELIVERY ALTERNATELY TO THE RESPECTIVE CRANK CASES BY REASON OF SAID PRESSURE DIFFERENTIALS. 